"We're looking for any information that anyone might have about the individual responsible for the killing of the carrier or what may have transpired right before or right after," Frank Schissler, a U.S. Postal Inspector and public information officer for U.S. Postal Inspection Service Agency, told ABCNews.com

According to the USPS, any person who kills or attempts to kill any federal officer or employee while they are on official duties could face the death penalty.

Anyone with information regarding the case is urged to call the U.S. Postal Inspection Service at 877-876-2455 or Prince George's County Police at 301-772-4925.

Barnette's death comes after a recent spate of attacks against postal workers over the last few months.

In a Tacoma, Wash., a postal worker was the subject of an unprovoked attack and punched three times while delivering mail. Another mail carrier was injured in Pennsylvania after he kicked a dog, thinking it was going to bite him, and the dog's owner started to hit him. In Springfield, Ohio a female postal service worker was groped while delivering mail.

In Beaumont, Texas mail service was suspended for a week after a postal service employee was attacked.